Enteral adenoviruses are a recently defined group of agents which cause gastroenteritis in children. They differ from other known human adenoviruses in their inability to be propagated in tissue culture. Adenoviruses recovered from patients will be examined for their relation to known respiratory adenoviruses by serologic, DNA hybridization, restriction endonuclease and protein electrophoresis studies. The mechanism of restriction of growth of these agents will be examined by nucleic acid hybridization, immunofluorescent microscopy and AAV helper studies. Attempts will be made to grow the viruses in tissue culture using adenovirus transformed cell lines and a series of early and late temperature sensitive mutants of adenovirus 5 as helpers. Enteral adenovirus-induced diarrheal illness will be studied in normal volunteers. The features of the illness, virus shedding and immune resolution will be examined.